The keyboard is an important tool for providing textual, command and other input to a computer or other electronic device. Although pointing devices (e.g., mice, touchpads, etc.), handwriting detectors (e.g., electronic digitizers and styli) and other input mechanisms continue to develop and offer numerous advantages in many situations, the keyboard will remain a primary input device for the foreseeable future. As critical as keyboards are, however, the basic design has remained the same for many years. In particular, a keyboard generally includes a matrix of electrical switches resting beneath a collection of keys. When a key is pressed, an electrical contact is made in the corresponding switch. A microprocessor periodically scans the switch matrix, and upon detecting a switch closure or opening, signals a press or release of a corresponding key.
Some alternative keyboard technologies have been developed. In some systems, for example, an image of a keyboard is displayed on a surface in front of a handheld computing device. Radar or another type of sensor within the computing device then detects a press of a projected “virtual” key when the user's finger is in the region corresponding to a projection of that key. Although useful, such technology is not a complete substitute for a mechanical keyboard. For example, many users rely on the tactile sensation of pressing keys; virtual keyboards do not offer this feature. Moreover, projected keyboards require a flat surface in order to function, and may not operate well in strong ambient lighting conditions.
Conventional keyboard technology limits the degree to which keyboard manufacturing costs can be reduced. A new key detection technology reducing or eliminating the need for a switch matrix, but maintaining the presence of actual keys providing a suitable tactile response and/or not affected by strong ambient light, would offer a significant advantage. Elimination of a switch matrix would also allow greater flexibility in changing the size and/or shape of a keyboard.